This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Recent live-cell imaging studies, coupled with a growing body of experimental genetic, biochemical and pharmacological data have expanded our knowledge of the molecular events that occur during endocytosis and the role played by actin (Toret and Drubin, 2006). In this collaboration we aim to develop a deeper understanding of endocytosis in yeast using correlated fluorescence and soft x-ray tomography to image the cellular ultrastructure of a number of different mutant endocytic phenotypes. The information obtained will not only highlight the effect of these mutations on the endocytic process and machinery, but establish the consequences of these changes on the organization of the entire cell. The cell cycle is the essential mechanism by which the cells of all living organisms from unicellular bacteria to the multicellular mammals duplicate. The most basic function of the cell cycle is to accurately duplicate the vast amount of DNA in the chromosomes and then segregate the copies precisely into genetically identical daughter cells. It has been shown that there is a general control that maintains a ratio of nuclear volume to cell volume. However, such correlation during the entire cell cycle has not been fully elucidated. In addition, it is very important to understand how other organelles are inherited during the cell cycle. Another goal of this collaboration is to use soft xray tomography to study the changes in organelle positioning and the volume and density of organelles during the phases of the cell cycle.